The present invention relates to an insulation-displacement connector.
It is known to make an electrical connection without having to prestrip the end of a cable to be connected. Several documents, such as Patent EP-0,247,360 for example, thus disclose an insulation-displacement connection arrangement with a slit for electrical wire, comprising a conducting connection piece with a straight stripping and retaining slit for the core of a wire. The slit is made longitudinally along a profiled part of the conducting piece.
There are several ways of introducing the end of a wire between the stripping and retaining slits of the conducting connection piece. In the aforementiond Patent EP-0,247,360, an external tool having an end-piece of suitable shape allows this wire to be introduced. As regards Patent FR-2,611,406, this provides a maneuvering piece molded with the casing and intended to serve as a pusher for making the end of the wire slip between the edges of the stripping slit. Other documents describe other examples of ways allowing the end of the wire to be introduced in order to make the insulation-displacement connection.
In known connectors, the conducting connection piece must firstly strip the wire and then make good electrical contact with it. It therefore must have good electrical conductivity properties, but also mechanical properties so as to guarantee that the sheath of the wire is cut and that there is sufficient contact force to make reliable contact. The materials known to be good conductors do not have the desired mechanical properties, especially from the elasticity standpoint, for allowing good stripping and satisfactory contact force.
When the conducting piece is not designed to take ends of wires which all have the same diameter, it is possible to adapt the shape of the connection piece in such a way that, by choosing a material having good or even excellent electrical properties, good stripping and an optimized contact force are achieved.
However, when the connection piece is intended to take ends of wires of different diameters, lying within a given range, it becomes difficult and even impossible to have both excellent results from an electrical standpoint and from a mechanical standpoint. The solution adopted therefore consists in making a compromise and in manufacturing the conducting connection piece from a material which has mechanical and electrical properties that are satisfactory without, however, being optimal. This requires the use of copper- and steel-based alloys which are relatively costly.
The object of the present invention is to provide a connector that does not require the use of an expensive material, while allowing satisfactory, or even very satisfactory, electrical and mechanical properties to be obtained.
For this purpose, the connector proposed by the invention is a slit-type insulation-displacement connector for electrical wire, comprising a conducting connection piece, with a stripping and retaining slit for the core of a wire, the slit being made longitudinally along a profiled part of the conducting piece.
According to the invention, this connector furthermore comprises a metal reinforcement made from a resilient material which follows the shape of the conducting piece by surrounding it.
Thus, the two functionsxe2x80x94electrical conductivity and elasticityxe2x80x94are decoupled. The connection piece provides the electrical conductivity while the reinforcement provides the elasticity necessary for effective stripping and good electrical connection.
In a first embodiment, the connection piece of the connector according to the invention has a hollow polygonal cross section in the region of the stripping and retaining slit.
In another embodiment, the connection piece of the connector according to the invention has an approximately V-shaped section in the region of the stripping and retaining slit, the slit being located at the tip of the V.
In order to provide good electrical conductivity, the conducting connection piece is preferably made of copper or of a copper-based alloy.
In order to guarantee good elasticity, the metal reinforcement is made of steel, for example.
In a first arrangement of the connector according to the invention, the metal reinforcement is fitted tightly over the conducting connection piece.
In this case, the reinforcement is, for example, a profiled piece having the same axis as the conducting connection piece and having approximately the same cross section but with slightly larger dimensions.
It is also possible to have, in the case of an arrangement in which the reinforcement fits tightly over the conducting piece, a conducting connection piece having two opposed stripping and retaining slits as well as a linking element placed on one side, adjacent to the slits in order to maintain the profile, and a reinforcement in the form of a profiled piece having an axis perpendicular to the stripping and retaining slits.
In another arrangement of the connector according to the invention, the metal reinforcement is fitted so as to slide with respect to the conducting connection piece, longitudinally with respect to the latter.
In this case, the reinforcement is advantageously acted upon by a spring, the latter being at rest in a covering position in which the reinforcement surrounds the connection piece over approximately the entire length of the reinforcement and a preloaded position in which only one end of the reinforcement surrounds part of the connection piece. The spring and the reinforcement can form only a single piece. The spring can therefore be deformed and the energy stored in the preloaded spring can then be used for introducing a wire to be connected into the stripping and retaining slit.
In the case of a connection piece having a V-shaped section and of a sliding reinforcement forming with the spring only a single piece, the reinforcement has, for example, a profiled part of triangular cross section, where the side of the triangular part which is opposite the stripping and retaining slit is extended so as to form a bent resilient blade; the bent part advantageously comes to bear against a stop which is fixed with respect to the connection piece; a recess is advantageously provided in the reinforcement at the profiled part in order to allow the end of a wire intended to be stripped to pass through the stripping and retaining slit and an opening is preferably provided in the resilient blade allowing a rod, such as the end of a screwdriver for example, to pass through it.